TR2/3/3A Draining and refilling TR3 transmission with OD

[Member 10617]

I knew how to drain and refill my TR3 transmission before I had an overdrive added, but now I am almost completely in the dark.
Can someone give me a quick lesson on how to do this?

I know where to fill the transmission (gearbox)-- no longer from the cabin but now from a plug in the side of the transmission. But now with overdrive there are two drain plugs(?) -- one the normal size under the transmission and the other larger with indentations all around the plug, located below the overdrive unit. When draining the transmission with OD, do both of these plugs need to be opened? Why two drain holes?

And when refilling, does the fill hole in the transmission also fill the OD portion?

ALSO: Is it even necessary to drain and refill the transmission (Gearbox) or just top it off every now and then. Some manuals recommend only topping off and not draining until unless the unit is overhauled. In automatic transmission cars, the transmission needs to be "flushed" now and then to maintain proper velocity.

I'm not having any noticeable problems, but just want to know how to conduct routine maintenance.

 

[trrdster2000]

Lextr3, You don't say if you are putting in a used tranny or did you have it rebuilt. If it's just needing topping up after a rebuild then just the side hole will do both at the same time. If you are draining because you don't know what has gone before in the overdrive then you will need to take out the big plug with the four notches in it. That is where the screen filter is and a magnet to catch all the little bits of metal, they will need cleaning, (carb cleaner). You can unscrew the big plug by tapping with a small bit of hard wood on the notch, or try a large pair of channel locks. Don't forget this is alumimumumumu!!!! CAREFULLY.

Of course oil has been discussed many times and from what I gather, 30 weight Valvoline racing oil for the overdrive is best.

Hope you are reading Hondo.

Wayne

 

[TR3driver]

To completely drain, you need to remove both plugs. There is also a screen and maybe some magnets inside the OD drain plug, that should be cleaned. The magnets are a worthwhile addition if you don't already have them (but they should be there if you have the plug with the notches). I also use a magnetic plug in the main gearbox.

I don't change oil as often as the book calls for (but I also use expensive synthetic manual transmission oil). However, I still think it should be changed from time to time, as not all of the dirt, wear particles, etc that accumulate will fall to the bottom, and anything that remains in the oil will accelerate the wear. The additives also wear out with miles and time, so another reason to change periodically.

The transmission fill also fills the OD. However, it does take some time for the oil to run into the OD, so it's worth taking a break after filling it the first time and fill it again after 15-20 minutes. The car should be level, of course.

BTW, my TR3 has the early top cover with the dipstick, with a later TR6 gearbox & a TR4 overdrive. It's not hard at all to convert the top cover to fit onto the later gearboxes.

 

[TR3driver]

You can unscrew the big plug by tapping with a small bit of hard wood on the notch, or try a large pair of channel locks. Don't forget this is alumimumumumu!!!!

Actually, the plug is brass, even softer than aluminum! I made up a tool to turn mine, after fighting the persistent leak caused by banging on it. Tool is simple, just a couple of bolts through a piece of flat iron bar, with nuts to hold them firmly to the bar and the bolts ground down to match the notches in the plug.

Some day, if I run out of better things to do, I plan to take a big socket and mill it to engage all 6 slots at the same time. But so far, the tool above has worked well for me.

If you want to use the Valvoline racing oil, I would suggest 20W50 rather than straight 30. You'll get easier shifts when cold, and more protection when hot.

But IMO Redline MT-90 is better than the racing oil.

 

[hondo402000]

I am reading Wayne!

Hondo

 

[hondo402000]

My Boat Uses 30 weight Synthetic oil, wonder if that will work?

Hondo

 

[Member 10617]

All this information is very helpful. Many thanks.

But I am a bit confused. My manuals call for Hypoid 80 for regular gear box (transmission). Before the transmission was rebuilt and the OD added, I was using NAPA Premium Performance hypoid gear oil, SAE 80W-85W-90 in the transmission. The shop that rebuilt the transmission filled it with oil, but I don't know what they used. I have been assuming it is the SAE 80W-85W-90 oil.

Isn't 30W too light?

 

[Member 10617]

Searching the internet, I have found the following interesting posting at BUCKEYE TRIUMPHS OHIO:

https://www.buckeyetriumphs.org/technical/Gearbox/GearboxLubricant/GearboxLub.htm

It raises as many questions as it answers, but it leads me to sticking with the GL4 Hypoid 80/90.

What I take away from the Buckeye posting is that any one of these oil will do (each has advantages and drawbacks), and none will damage the gearbox. GL4 is what Triumph originally recommended, so perhaps it is best to stick with it.

 

[hondo402000]

its funny in the bently manual it list 90 wt for transmission and overdrive
it also says top off oil in transmission every 6000 miles and I quote "an oil transfer hole between the transmission and OD unit provides a common oil level Maintenance of the OD unit is thus limited to ensuring that the correct oil level is maintained in the gear box" So why in the *(&*^**^ did laylock put a drain plug in the OD unit and a Screen filter!!! and no less Standpart put a drain plug in the Transmission too! So I guess in the maintenance program it must say, Drive car till Overdrive and transmission break and replace with NEW unit

Hondo

 

[TR3driver]

Even stranger, Laycock specifically warned against using "hypoid" oil in the A-type OD. There is even a very early service bulletin from the factory, noting that they had a failure that was attributed to using EP oil in the OD, and rescinding the previous approval for using same:

<span style="font-style: italic">The “Recommended Lubricants — Overseas” chart in our Instruction Books and Service Manual gives the alternative of either Hypoid or normal Mineral oils for gearboxes operating in the “over 10
Fahrenheit” and “over 70
Fahrenheit” ranges. This recommendation is not applicable where overdrive units are fitted and your garage personnel, and customers where necessary, should be advised of the fact.</span>

And the TR6 factory manual does give a procedure for draining the OD, even though there is no schedule (that I can find) for doing so.

 

[TR3driver]

Isn't 30W too light?

The "weight" numbers are deliberately different between "motor" oil and "gear" oil. "30 weight" (there is actually no such spec as "30W" since the "W" stands for "Winter" rather than "weight") motor oil is actually about the same viscosity (at the same temperature) as 85W gear oil.

More at
https://www.micapeak.com/info/oiled.html

 

[TR3driver]

My Boat Uses 30 weight Synthetic oil, wonder if that will work?

Might be OK, but it might not. Most likely, your boat does not have synchronizer rings. But TR gearboxes do have synchronizers, which rely on a certain level of friction for operation. Some synthetic gear oils are too "slick" for good synchronizer operation/life, perhaps the same thing applies to some synthetic motor oils.

Bottom line, I think practically anything will "work", for awhile. The differences are mostly in the realm of working longer and better. I don't have enough miles on the MT-90 yet to say if it really helps with longevity, but it does make both the gearbox and OD shift in a noticeably less "agrarian" fashion!

 

[HerronScott]

Here's the care and lubrication section from an early service instruction manual for the A-type overdrive (only mentions TR2) showing the warning Randall mentioned.

Care and Lubrication

The oil in the overdrive is common with that in the gearbox. The oil to use is ordinary mineral oil in the following grades :

Normal summer climates — S.A.E.30
Normal winter climates — S.A.E.20

Under no circumstances should extreme pressure gear oils be used, because the centrifugal effect of the planets may separate some of the additives from the oil and cause sludging. The oil capacity of the gearbox and overdrive unit is as follows: —

Standard Vanguard and Triumph Renown — 3.5 pints (2 litres)
Triumph TR2 — 3.5 pints (2 litres)

The correct level must be carefully maintained. It will be necessary to remove the drain plugs from both gearbox and overdrive unit to drain them, but refilling is done through the gearbox only.

Refill the gearbox with oil after draining and then drive the car a short distance, after which top up with oil because some of the oil will have been taken into the hydraulic system. Do not run the car with no oil in the unit because air may enter the hydraulic system.

Cleanliness is the keynote to satisfactory performance of any hydraulic system. The smallest amount of dirt or "fluff" from a wiping cloth which finds its way into a valve will cause a great deal of unnecessary difficulty. Pay particular attention to the clean condition of the oil used for filling, and carefully clean all around the filler plug each time before removing it. Regular attention to these small details will be rewarded by long and trouble-free service.

 

[TR3driver]

Just to round out the story, Triumph/Leyland changed their recommendation around 1960 to using only GL4 (not motor oil) in the gearbox whether or not an overdrive was present. The legend as I heard it was that they were having too many failures under warranty of the gearbox countershaft thrust washer; and felt that using GL4 instead of motor oil would reduce the overall number of returns during the warranty period.

Whether or not Laycock (the makers of the overdrive unit) ever approved this change is unclear, until the introduction of the J-type OD (which will work on almost anything including ATF and probably baby oil

)

 

[Twosheds]

Isn't 30W too light?

The "weight" numbers are deliberately different between "motor" oil and "gear" oil. "30 weight" (there is actually no such spec as "30W" since the "W" stands for "Winter" rather than "weight") motor oil is actually about the same viscosity (at the same temperature) as 85W gear oil.

More at
https://www.micapeak.com/info/oiled.html

Thanks, Randall.

 

[hondo402000]

I had a 63 volvo with an A type laylock overdrive in college and the manual said SAE 30 motor oil. I drove it at least 100K miles and had no problems with either OD or transmission

how about 50/50 SAE 30 motor oil and 85/90 gear oil, that should make everyone happy

hehe

Hondo

 

[Member 10617]

All very interesting. Many warm thanks Randall for menioning the equivalency of gear oil with motor oil. I believe I am going to continue using the hyploid gear oil 80W-85W-90 in my gearbox/OD until I sense a problem with the transmission. I think that if I make sure it is always topped off, most of the problems may be avoided.

Thus far, my shifting is smooth and sure.

 

[Member 10617]

More on this topic.

I came across a posting from Quantumechanics, posted in 2005, on the subject of overdrive oil recommendation.

The author notes the inconsistency in recommendations from various car manufactures. MG manuals say to use multi grade oil, Triumph manuals say use hypoid oil, some call for non detergent oil, and some recommend atuomatic transmission fluid.

The author conducted an experiment by trying each oil or fluid and measuring pressure. The 30W, non detergent motor oil worked best. The 90 weight hypoid oil took the pressure too high and,in some cars, caused excessive wear on the oil pump plunger wheel and the eccentric cam. He also noted deterioration of the clutch linng in units with 90 weight oil. He concluded: "The use of non detergent 30 weight oil does not seem to affect the transmission parts or function. Bearings, synchros, gears and hubs do not seem to function any less effectively with the non detergent 30 weight oil as with 90 weight gear oil.... our scientifically based rationale for using and recommending 30 weight non detergent oil in Laycock overdrives.."

Since, as Randall says, 30 weight motor oil is about the equivalent of 80W-85W-90 hypoid gear oil, doesn't it make sense to use the 30 weight non detergent motor oil?

 

[TR3driver]

Since, as Randall says, 30 weight motor oil is about the equivalent of 80W-85W-90 hypoid gear oil, doesn't it make sense to use the 30 weight non detergent motor oil?

If you poke around a bit on that site, you can also find where he notes that the countershaft thrust washers are a particular weak spot in the Triumph TR2-6 gearbox, and he recommends having the case machined to accept the more robust components (Torrington bearing rather than plain thrust washer) used in the otherwise similar Stag gearbox. This would seem to lend credence to the legend (which reportedly came from ex-Triumph engineers) about why Triumph recommended gear oil rather than motor oil from about 1960 onwards.

It also seems to me that his experiments must not have been done with a Triumph gearbox, as he reported instant failure using gear oil; while the TRs came from the factory with gear oil and clearly did not fail instantly. In fact, his report makes no sense at all to me, since even 30 weight motor oil is thicker at some temperatures, than 90 weight gear oil is at the temperature he was running his tests at. IMO the high pressure he saw had to be due to something else (like perhaps grit caught in the pressure control valve or even coil bind due to too many spring shims installed). Note that he doesn't even specify which overdrive his experiments were done with (there are at least 4 distinctly different models of Laycock overdrive and of course myriad variations of each model). If you read through Nelson's much more detailed article at
https://www.buckeyetriumphs.org/technical/AOD/AOD4/AOD4.htm
you can see some similar results, which he traced to other explanations.

In other words, sauce for the goose ain't necessarily sauce for the gander; and there is a lot to be said for following the manufacturer's recommendation (especially since they were responsible for warrantying a whole lot more Triumph gearboxes than John will ever be).

It also seems just a bit self-serving to recommend using an oil that provides less protection; while simultaneously making a profit from upgrading gearboxes to survive with less protection. Certainly the appearance of a conflict of interest there.

BTW, when I had Herman van den Akker rebuild my A-type (at the time, he was the premier west coast overdrive gearbox specialist, although he has since moved on to Toyota conversions instead); he specified the Valvoline 20W50 racing oil. Which, unlike 30 ND, has ZDDP that acts like an extreme pressure additive and helps protect the thrust washers. Ken Gillanders (British Frame and Engine) also did a long term test of the VR1 20W50 in his ex-racing TR2 (with A-type OD) and reported no measurable wear or malfunction in 5 years of frequent operation.

 

[Member 10617]

Many thanks Randall for all this good information. I have learned a lot, and am still learning.

A friend of mine who works in a Triumph shop up the road told me this morning that they use 40W Amalie oil because the lighter oil is better on the overdrive. Any thoughts on this?

Your mention of the Valvoline 20W-50 Racing Oil makes me think that this might be an excellent alternative to all the others. I've come across this elsewhere.